KR20020016314A - The method of checking and removing residues in a contact-hole - Google Patents

Abstract

PURPOSE: A method for inspecting a contact hole and removing residue is provided to prevent a loss of a wafer and to simplify a fabricating process, by inspecting and eliminating the residue in the contact hole without sawing the wafer. CONSTITUTION: The contact hole is formed in a semiconductor device. A plasma treatment process is performed regarding the wafer(22) to eliminate the residue inside the contact hole. Predetermined light is irradiated to the plasma-treated wafer. A signal value regarding reflected light is detected and schematized. The abovementioned processes are repeated to form an excellent contact hole.

Description

Contact Hole Inspection and Residual Removal Method {THE METHOD OF CHECKING AND REMOVING RESIDUES IN A CONTACT-HOLE}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a manufacturing process of a semiconductor device. In detail, a semiconductor device to be completed by performing residue removal and inspection of an inside of an etched contact hole without cutting the wafer on which the contact hole is formed to ensure accuracy of the etching process In order to improve the properties of the contact hole inspection and residue removal method.

The contact of the metal filling process of the semiconductor device is exposed to a predetermined pattern and then etched to form a contact hole, and the formed contact hole is filled with a metal. In this process, the contact hole formed is inspected. Included.

For example, in the conventional 0.18 mu m wide contact process of the litho process, a contact hole is formed by applying a resist and then etching the interlayer insulating film and the gate film on the contact forming portion after exposure. Thereafter, a predetermined portion of the wafer is cut, and then the formation of the contact hole and the etching state are examined by observing the cut portion with an electron microscope.

1 is a cross-sectional view of a wafer cut to inspect contact holes etched by a conventional method.

As shown in Figure 1, by examining the etched contact hole it can be seen that the residue remains inside. As such, if the process of inspecting the formed contact hole is not accompanied, a residue remains inside the contact hole, and thus a semiconductor device having good characteristics cannot be manufactured even if a contact hole is formed by filling a conductive material in a subsequent process, and thus, the contact hole The inspection process is a process necessary for forming good contacts and improving the characteristics of the semiconductor device.

However, the conventional contact hole inspection process described above has a problem in that the wafer is cut during the semiconductor manufacturing process. This unnecessarily wastes the wafer, loses time and is a major obstacle to the smooth process. In addition, when the semiconductor manufacturing process is abnormal, the process conditions change, and when the etching and the inspection and inspection are to be performed, it causes a big step in the process and the yield.

Accordingly, an object of the present invention for solving the above problems is to remove the residue and inspect the inside of the etched contact hole without cutting the wafer using a predetermined inspection device to ensure the accuracy of the etching process of the semiconductor device To improve the properties, to provide a contact hole inspection and residue removal method.

1 is a cross-sectional view of a wafer cut to inspect contact holes etched by a conventional method.

2 is a view showing an FT-IR inspector used for contact hole inspection according to an embodiment of the present invention.

3 is a view showing a result of measuring the peak value of the reflected infrared rays according to the number of plasma treatment in one embodiment of the present invention.

<Description of Symbols for Main Parts of Drawings>

21: inspection device 22: wafer

23: infrared generator 24: polarizer

25: detector

The contact hole inspection and residue removal method according to the present invention is a wafer in which a contact hole of a semiconductor device is formed,

A first step of treating the wafer with plasma to remove residues in the formed contact holes, and projecting a predetermined light onto the plasma-treated wafer and detecting and plotting signal values for light reflected therefrom. Includes two steps.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

2 illustrates an FT-IR inspector used for contact hole inspection according to an embodiment of the present invention.

In the FT-IR (Fourier Transform-InfraRed) tester, the sample to be analyzed is formed into a thin film using infrared rays, and then the infrared rays are passed through to draw a signal detected by the opposite detector on a graph. Examine the components of the sample.

In this embodiment, however, the signal cannot be detected by passing infrared rays through the residue of the contact hole. Therefore, once the infrared rays are projected onto the wafer, the signal for the reflected infrared rays is detected by the detector to analyze the peak value to detect the presence of the residue. Check it.

In this embodiment, first, in a semiconductor manufacturing process that proceeds in a lot unit, two wafers are taken out of one lot, and one wafer is left as it is, and the remaining one wafer is treated with plasma for a short time, that is, about 5 minutes.

Thereafter, as shown in the drawing, the wafer 22 treated with plasma is first mounted on an inspection table inside the inspection apparatus 21. Afterwards, the infrared rays emitted from the infrared generator 23 are projected onto the wafer 22 through the polarizer 24, and the infrared rays reflected from the wafer 22 are detected by the detector 25 to graph the peak value of the infrared signal. Draw it.

3 is a view showing a result of measuring the peak value of the reflected infrared rays according to the number of plasma treatment in this embodiment. In FIG. 3, the measurement results of the infrared peak values after three plasma treatments are shown. The horizontal axis represents frequency and the vertical axis represents peak value of reflected infrared light.

As shown in FIG. 3, in the present invention, when the number of plasma treatments is increased in an etched contact hole, a change in the contact hole may be observed. As the number of plasma treatments increases, residues decrease. Thereafter, the plasma processing is performed a predetermined number of times, and if the internal state is less, even if the number is increased, the plasma processing is stopped at a predetermined time and the next process is performed.

Therefore, as described above, the present invention effectively performs inspection and residue removal inside the contact hole without cutting the wafer.

As described above, the present invention removes and inspects residues in the contact holes without cutting the wafer, thereby preventing the loss of the wafer and eliminating the process, thereby improving the characteristics of the semiconductor device and simplifying the process. There is an effect that can be.

Claims (5)

In a wafer in which contact holes of a semiconductor element are formed, A first step of treating the wafer with plasma to remove residues in the formed contact holes; And, And projecting predetermined light onto the plasma-treated wafer and detecting and plotting signal values for light reflected therefrom. The method of claim 1 wherein the method And repeating the first and second steps, thereby forming the contact hole satisfactorily. The method of claim 1 wherein the method Contact hole inspection and residue removal method characterized in that the inspection using the FT-IR inspection. The method of claim 1, wherein the second step Contact hole inspection and residue removal method, characterized in that using the infrared light as the predetermined light. The method of claim 1, wherein the second step Contact hole inspection and residue removal method characterized in that the plotted to the peak value for the reflected light.